Stabilization of aldehyde products



Patented May 21,1935

; um n Sim-res j FATE-m macs f a'ooisss r STABILIZATION F 'ALDEHYDE PRODUCTS 'Percy Joshua Leaper Naugatuck, Conn assignor by mesne assignments, to United States Rubber Company, NewvYork, N. Y., a corporation i of NewJersey' No Drawing; Application April 'JpSeriaI NIP-667,042 p llllaims; (ores-250) This invention relates to the. preservation and stabilization of certain aldehyde productsand to the resulting stabilized compositions; 'Among the difiicultie's attendantlrthe manufacture* and use of certain perfumery intermediates is the difficulty of suitably protecting them against-the effects ofoxygenduring their manufacture and also duringtheir subsequent storage and use. Of importance amongsuch perfumery 10. chemicals are certain unsaturated aromatic aldehydesandipartially oxidized unsaturated aromatic aldehydesi Perfu'mery chemicals are now purchasedg blended, and sold on the final criterion of smell orodor r ather than purity. The :inventorhas recognized that these differences in shade and tone' arefreduently due to the presence of partially oxidized chemicals. In some instances in the -perfumerytrade the presence of such partially oxidized materials is required along with the unoxidized chemicals, for the purpose of duplicating and matching the odor of.

perfume products, but unless the state of oxidation oi -the partially oxidized materials and' the state of the unoxidized products is preserved, undesirable acid substances are formed by autooxidation; resulting in objectionable smell or rancidity which seriously interferes with thekcommercial value of the'products. One of the aldehydes which is notorious for this misbehavior is amyl cinnarnic aldehyde havingthe formula This material undergoes a complex auto-oxidation whencsubjected-to the influence of oxygen, the end products probably being benzoic and ncaproic acids. f r l In the manufacture of amyl cinnamic aldehyde, thefamyl cinnamic aldehyde is separated rise in acidf'content during storage and use.

Whilea certain amount 'of autooxidation may be desirable in-some cases uncontrolled autooxidation is not desirable. l

7 An object oi 'this invention is to provide a statbilized standardized amyl 'cinnam ic aldehyde, and stabilized standardized mixtures of the same with oxidation products'having thedesired odor. The individual perfume manufacturer has become accustomed to the use ofintermediates containing these oxidation products in amounts dependent on the particular method ofp'reparation and equipment used. Consequently, it frequently happens that the perfume manufacturer rejects v and refuses to accept a shipment of perfumery chemicals, which may contain. higher or lower amounts of oxidation products than in previous shipments, solely onthe basis or sense of smell, even though the chemicals in. question. are of higher purityand quality. By standardized is meantthe property of being predetermined'and fixed witlrrespect to desired components by the substantial prevention oryretardation of oxida-' tion in thealdehyde or the stabilization or preservation against oxygen of-any mixture of the same as the case may be during and/or subsequent'to preparation. Aiurther object is to prepare a standardized amyl cinnamic. aldehyde to which any desired concentration of partially oxidized amylcinnamic aldehyde may be added to produce a blend which will be'more suitable for perfumery compounding, and which will retain its good qualities for a considerable time even though exposed to oxidizing' conditions. Other objects will be apparent from the following description.

EmampZeIP-A stabilized amyl cinnamic aldehyde is produced by adding thereto a small proportion, for example by weight, of diphenylamine; The effectiveness of the anti-oxygen is measured by exposing'thinfilms of the mixtures in fiat dishes under free circulation or" air: and

.measuring periodically theextent of freetacidity developed,,as determined in a small aliquot portion. The increase in acidity is a measure of the speed and extent of oxidation. The figures under Changein acidity in Table I show the milligrams of potassium hydroxide required to'neu- .tralize the acid formed in one gram sample during progressive oxidation. For purposes of comparison in each case a similar mix is placed in afconta'iner and sealed against exposure to. air Hand kept so for corresponding lengths-{of time. The sameprocedur'esare carried out with a blank (identical with the exposed sample); containing no anti-oxygen, which is made up and subjected to the same conditions as those imposed upon the I exposed mixture. The results are tabulated as follows:

and. partially oxidized aldehyde may be developed TABLE I Exposed for 170 hours Exposed for 336 hours Acidity of Acidity of Acidity of Acidity brsesled exposed 523 sealed exposed fggg: sample sample y sample sample I y 1 No antioxidant (Blank) 1. 45 102.7 +101. 25 1.15 128.2 +1210 2 Diphenyhminp 1,04 1.03' 0.'01 0.95 1.38 +0.43

The-stabilization or preserving characteristics 7 of diphenylamine seems to be specific to. it and not attributable to the whole chemical class the final perfume blend. 7

Beneficial results are also obtained by adding the anti-oxygen during the processing of the amyl cinnamic aldehyde, that. is adding same to color, volatility, etc. and its specific effects on the unpurified amyl cinnamic aldehyde prior to the final separation by vacuumdistillation from associatedmaterials formed or present during the process of manufacture.

It has also been found that when the antioxygen is added to a partially oxidized amyl cin-:

namicaldehyde either directly as such or indirectly in the form of a stabilized aldehyde that the same beneficial properties are obtained as when added to a pure unoxidiz'ed' material.v This statement may be verified by referring to. Table II wherein diphenylamine is added, in turn, to various mixtures of pure stabilized amyl cinnamic aldehyde and well oxidized amyl cinnamic aldehyde. The termfwell oxidized as used in Table II is intended to refer to an unprotected amyl cinnamic aldehyde whichhasbeen exposed for a sufficient period of time .in: air until a marked increase in acidity has been noted. The

rate of oxidation may be hastened by elevating the temperature or by increasing the'air-surface interface of'the amyl cinnamic aldehyde or by passingoxygen into the liquid aldehyde.

I TABLE II Stabilieationof blends of well oxidized amyl cinnamic aldehyde and pure aldehyde (Diphenylamine used asanti-ogtqgen) I Acidity determined alterv Percentage Percentage V of Oxidized s a b l i d 168 hours 4081101113 aldehyde M Blending, we f fr used 3 11 591 e prior to ei posure e pos ie exposure to air -'to air 1 0.5 99.5 1.0 I 1.0 1.- 2 1.0 99.0 1.6 1.2 1. 3 1.5 98.5 1-7 1.6 1. 4 2.0 98.0 2.3'- 1.8 2. 5 3.0 '97.) 2.8 2. 6 4-0 96.0 3.4 2-8 V 3. 7 5.0 95.0 4.4 3.7 3. s 7. 5 92. 5 r 5. 8 1 5.6 a 5. 9. v 10. 0 9,0. 0 7. 9 7. 3 7. 10 15.0 85.0 11.7 10.7 '10. 11 20. I 80. 0, V 15. 7 14. 6 14; '12 25.0 75.0 19.7 I 18.0 v 18. '13 100. 0 80. 0 119. 5' 127. 14 100.0 1.1. 116, o.

to satisfy the'requirements of the perfumery trade by the control process of this invention.

anti-oxygen is added to stabilize the pure amyl cinnamic aldehyde used in Table II and none in the. oxidized aldehyde;. it will be foundthat the proportionof anti-oxygen in the aldehyde to be a stabilized may be varied from about 0.1% to 1% with similar beneficialresults.

It will be obviousto those skihed in the art that the duration andeliectivenessof the protec-f tionafiordedthe amyl cinnamic'aldehyde by the anti-oxygenwhen addedprior to or during the vacuum distillation step, is dependent on the volatility of the anti-oxygen under these. conditions, and, in certain instances, may remain behind in the still residue. In this event, it has been found desirable to add .a small amount of the anti-oxygen to the aldehyde after distillation to stabilize same during storage and use.' The invention discloses a practical method of stabilizing any amyl cinnarnic' aldehyde prepared according 1 to present practice (and, hence, containing varying amountsof' oxidation products)- against further oxidation and change in'odor during storage and use. Finally, theinvention provides a convenient means or" duplicating the desired odors of aldehyde products, which for the first time, may be controlled by acid number determinations.

Having described the inventioinit will be clear that variouschanges may be made in the application thereo-f'without departing from the spirit and scope of the invention and it is notdesired to limit the invention otherwise than as set forth in the appended claims. 7

Having thus described my invention, what I claim and desireto protect by Letters Patent is:

1. A process of improving; the perfume characteristics of an amyl'cinnamic aldehyde as commercially prepared which comprises adding there to a small amount of. diphenylamine. i y

2; Aprocesscofcontrollingthe perfume tone-of amyl cinnamic aldehyde: which comprisesadding to amyl cinnamic aldehyde a smalliamountiof .diphenylamine. V

' enoit JOSHUA. LEAr R:

One-half of one'percent (by Weight) of the 

